Linksys WRTSL54GS and ASUS WL520GU : Tomato Possibilities

I have one Linksys WRTSL54GS with Tomato 1.27 ND USB + VPN Mod running at home with DSL modem connected in bridge mode. The internal network address for the router is ( 192.168.1.2 / 255.255.255.0)

Now I have got another router ASUS WL520GU (which can supposedly run tomato and/or DD-WRT as well, havent tried as yet).

I just want to ask what is the best way to connect two routers in wireless mode. So maybe they can create a big WLAN and can extend the reach of the existing wireless network. Any other practical and interesting suggestion to use two routers is also welcome.

What mode and/or specific settings I have to make on the first or the second router to make them cover the same wireless network (maybe with the second router acting as a repeater to extend the range).